Add bigger cell phone bills to the list of challenges brought on by the white-hot bring your own device (BYOD) trend.

Rising data costs are becoming a cause of concern for IT managers around the world according to the results of a survey from iPass and MobileIron. Fifty-seven percent of the 477 IT executives polled by the companies said that they expect their mobile data roaming costs to rise this year.

Some IT managers expect those costs to rise sharply. Eight percent said that their data roaming charges will balloon by more than 25 percent.

A big reason that BYOD programs are growing more expensive is that people are simply hooked on their smartphones and tablets. Forty-four percent said that supporting more devices per worker is raising costs. Mobile carriers are doing their part to keep costs high, say 41 percent of respondents who singled out high-priced 3G and 4G data plans.

Each mobile worker costs IT departments an average $96 a month on data fees alone, according to the report. North America pays the highest fees at $97 per month.

Budgetary concerns aside, the top two frustrations expressed by IT managers were onboarding smartphones and tablets and then supporting the sheer volume of device types. Fifty-five percent experienced a security issue over the past year, mostly involving lost or stolen phones.

The report contains some encouraging news for Microsoft. Forty-five percent of those surveyed said that they plan to support Windows Phone 8. For BlackBerry 10, that number dips to 34 percent.

The firms also discovered that control over mobile spending is slipping out of the grasp of IT departments.

IT departments manage the mobile budgets for less than half (48 percent) of the enterprises surveyed for the report. Non-IT departments are currently managing mobility spend for 40 percent of the organizations.

This trend of shifting the responsibility for mobile spending away from IT is the reason that mobile data costs are rising, according to iPass chief technology officer Barbara Nelson.

"IT is charged with implementing solutions to boost employee productivity, and BYOD does that. But as more personal mobile devices with multiple platforms and operating systems are used for work, IT managers are challenged to safeguard corporate data and keep roaming costs low," explains Nelson in a statement.

Take that oversight away and budgets suffer. "And when mobility budgets are managed by departments rather than IT, data roaming costs can be hard to control," added Nelson.